Chorioretinopathy with Microcephaly 2
Patient Information
Characteristics
Background and History
Many gene mutations impact brain development and function. In addition, there are often more widespread problems in the eye and other organs with intellectual disability and psychomotor retardation as in this disorder.
Clinical Correlations
A small head with a sloping forehead is characteristic. The eyes may also be small in size with internal malformations (involving the vitreous and retina) that result in poor vision. The corneas (windshields of the eye) may be small and malformed. Some eyes have variants of a retinal detachment. Cataracts may be present.
There is general growth retardation and usually marked intellectual disability. Seizures may occur. Physical growth is slow and those individuals that survive beyond childhood are short in stature. Sitting is delayed and walking requires assistance. Hearing loss has been reported. Abnormal spinal curvature is sometimes present and sometimes the digits such as fingers and toes are mildly malformed.
Radiological imaging reveals undeveloped and malformed brain structures.
Genetics
Inheritance
This condition is caused by a mutation that must be present in both copies of a specific gene. The parents with one mutated copy are clinically normal but when both are carriers, they can expect that 1 in 4 of their children on average have this disorder.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
Diagnosis and Prognosis
The small head and sloping forehead are evident at birth. Pediatricians, neurologist, geneticists and ophthalmologists may be involved in the evaluation of such infants. There is no known treatment although physical therapy may prevent joint contractures. Physical care is mainly supportive. Longevity is shortened although patients may live into the second decade.
Web Resources
Printer Friendly Version: Ctrl/Cmd+P